TCXO products come
equipped with a frequency adjustment feature that allows for adjustments
to the center frequency. This feature allows compensation for initial frequency
calibration and aging, and is accomplished via the internal trimmer. This
adjustment can also be provided by a control voltage via an external lead
on the TCXO The oscillator utilizing this technique is referred to as a
Temperature Compensated Voltage Controlled Crystal Oscillator or TCVCXO.